Latch pin assemblies may be used in applications requiring latching and locking of movable structures, such as folding wing tip systems used on aircraft. An airport taxiway and/or gate may have space (e.g., width) limitations, which limit a wingspan of an aircraft that may use the taxiway and/or the gate. However, the wingspan of the aircraft may correspond to a maximum possible passenger volume and/or cargo volume of the aircraft. Thus, to service a greater number of passengers, decrease fuel consumption and/or transport a larger amount of cargo, employment of an aircraft with a wingspan exceeding the space limitation of the taxiway and/or the gate may be desirable.
To employ an aircraft having a wingspan greater than the space limitation of a taxiway and/or a gate, the aircraft may be configured to have folding wing tip system for folding the tips of the wings to enable the aircraft to fit within the taxiway and/or the gate. Should the folding wing tip system fail to operate, however, it may prevent the aircraft from entering the taxiway and/or the gate. This not only affects the aircraft outfitted with the folding wing tip system, but also may also block other aircraft from entering the taxiway or gate, thereby causing a major disruption of airport operations. Thus, it is advantageous to provide a folding wing tip system that is highly reliable.
The wing tips may be secured in the spread position using latch pin assemblies. Latch pin assemblies typically include one or more latch pins sized for insertion through lugs provided on the fixed wing portion and wing tip. A latch pin actuator may move the latch pins between an extended position, in which the latch pins are inserted through the lugs to hold the wing tips in the spread position, and a retracted position, in which the latch pins are withdrawn from the lugs to permit the wing tips to be rotated to the folded position.
The latch pin assembly may further include a lock sub-assembly to lock the wing tips in the spread position during flight. The lock sub-assembly may include redundant locking mechanisms to ensure that the wing tips remain in the spread position in the event one of the locking mechanisms fails. For example, U.S. Pat. No. 5,201,479 to Renzelmann (‘the '479 patent’) discloses a latch pin lock for a folding wing aircraft that includes a primary lock having a primary locking body that mechanically engages the pin, and a secondary lock having a separate, secondary locking body that mechanically engages the pin independent of the primary locking body. While the '479 patent discloses a locking arrangement that reliably secures the pin in the extended position, the use of multiple, independent locking bodies requires additional space, adds weight to the aircraft, and introduces operational complexities.